arithmetic boats and streams questions and answers paper 358 - skillgunNote: Paper virtual numbers may be different from actual paper numbers . In the page numbers section website displaying virtual numbers .
A man's speed with the current is 20 kmph and speed of the current is 3 kmph. The Man's speed against the current will be
If you solved this question yourself, then trust me you have a all very clear with the basics of this chapter.
If not then lets solve this together.
Speed with current is 20,
speed of the man + It is speed of the current
Speed in still water = 20 - 3 = 17
Now speed against the current will be
Speed of the man - speed of the current
= 17 - 3 = 14 kmph
A man takes twice as long to row a distance against the stream as to row the same distance in favour of the stream. The ratio of the speed of the boat in still water and stream is
2 : 3
3 : 4
3 : 1
Let speed downstream = x kmph
Then Speed upstream = 2x kmph
So ratio will be,
=> (2x+x)/2 : (2x-x)/2
=> 3x/2 : x/2
=> 3 :1
If a boat goes 7 km upstream in 42 minutes and the speed of the stream is 3 kmph, then the speed of the boat in still water is:
Rate upstream = (7/42)*60 kmh = 10 kmph.
Speed of stream = 3 kmph.
Let speed in sttil water is x km/hr
Then, speed upstream = (x - 3) km/hr.
=> x-3 = 10
or x = 13 kmph
A man can row upstream 10 kmph and downstream 20 kmph. Find the man rate in still water and rate of the stream.
If a is rate downstream and b is rate upstream
Rate in still water = 1/2(a+b)
Rate of current = 1/2(a-b)
=> Rate in still water = 1/2(20+10) = 15 kmph
=> Rate of current = 1/2(20-10) = 5 kmph
A man takes 3 hours 45 minutes to row a boat 15 km downstream of a river and 2 hours 30 minutes to cover a distance of 5 km upstream. Find the speed of the current.
Speed of current = 1/2(speed downstream - speed upstream)
So we need to calculate speed downstream and speed upstream first.
Speed = Distance / Time [important]
Speed upstream =(15334)km/hr=15×415 = 4 km/hr
Speed Downstream = (5212)km/hr=5×25 = 2 km/hr
So speed of current = 12(4-2) =1 km/hr
In one hour, a boat goes 11 km along the stream and 5 km against it.
Find the speed of the boat in still water:
We know we can calculate it by 1/2(a+b)
= 8 km/hr
A motorboat, whose speed in 15 km/hr in still water goes 30 km downstream and comes back in a total of 4 hours 30 minutes. The speed of the stream (in km/hr) is:
Let the speed of the stream be x km/hr. Then,
Speed downstream = (15 + x) km/hr,
Speed upstream = (15 - x) km/hr
So we know from question that it took 4(1/2)hrs to travel back to same point.
=> 900/(225-x^2) = 9/2
=> 9x^2 = 225
=> x = 5 km/hr
A man rows 750 m in 675 seconds against the stream and returns in 7 and half minutes. His rowing speed in still water is
Rate upstream = (750/675) = 10/9 m/sec
Rate downstream (750/450) m/sec = 5/3 m/sec
Rate in still water = (1/2)*[(10/9) + (5/3)] m/sec.
= 25/18 m/sec
= (25/18)*(18/5) kmph
= 5 kmph
A man can row upstream at 8 kmph and downstream at 13 kmph.
The speed of the stream is :
Speed of stream =>
= 1/2 (13-8) kmph
= 2.5 kmph
A boat goes 13 km upstream in 39 minutes. The speed of stream is 3 km/hr. The speed of boat in still water is:
none of the above
Speed of the boat upstream= 13 x 60/39= 20 km/hr
Speed of the stream = 3 km/hr
Let the speed of the boat in still water = x km/hr
We have, x - 3 = 20
=> x = 20 + 3
=> x = 23 km/h
A boat running downstream covers a distance of 16 km in 2 hours while for covering the same distance upstream, it takes 4 hours. What is the speed of the boat in still water ?
Rate downstream = 16/2 kmph
= 8 kmph
Rate upstream = 16 /4 kmph
= 4 kmph
Speed in still water = 1 /2 (8 + 4) kmph
= 6 kmph
In one hour, a boat goes 11 km along the stream and 5 km against the stream. The speed of the boat in still water in ( km/hr) is
Speed in still water = 1 / 2(11 + 5) km/hr
= 8 km/hr.
A man can row three - quarters of a kilometer against the stream in 11¼minutes. The speed(in km/hr) of the man in still water is
Rate upstream = (750 / 675)m/sec
= (10 / 9) m/ sec.
Rate downstream = (750 / 450)
= (5 / 3) m/sec
Rate in still water = 1/2(10 /9 + 5/3)
= 5 km/hr.
If a man rows at the rate of 5 kmph in still water and his rate against the current is 3.5 kmph, then the man’s rate along the current is
Let the rate along the current be x kmph.
Then, = (1 / 2(x+3.5))= 5
=> x= 6.5 kmph.
Speed of a boat in standing water is 9 kmph and the speed of the stream is 1. 5 kmph. A man rows to a place at a distance of 105 km and comes back to the starting point. The total time taken by him is :
Speed Upstream = 7.5 kmph.
Speed Downstream = 10.5 kmph.
Total time taken = [10.5/7.5 + 105/10.5] hours
= 24 hours
A boat takes 90 minutes less to travel 36 miles downstream than to travel the same distance upstream. If the speed of the boat in still water is 10 mph, the speed of the stream is
Speed downstream =(10 + x)mph.
Speed upstream = (10 - x)mph.
= 18 kmph.
36/(10-x) - 36/(10+x) = 90/60
= 72x ×60
= 90(100 - x²)
=> x² + 48x + 100 = 0
=> x = 2 mph
A boat can travel with a speed of 13 km / hr in still water. If the speed of the stream is 4 km / hr. find the time taken by the boat to go 68 km downstream?
Speed Downstream = (13 + 4) km/hr
= 17 km/hr.
Time taken to travel 68 km downstream = (68 / 17)hrs
= 4 hrs.
A boat takes 19 hours for travelling downstream from point A to point B and coming back to a point C midway between A and B. If the velocity of the stream is 4 kmph and the speed of the boat in still water is 14 kmph, what is the distance between A and B ?
Speed Downstream = (14 + 4) km/hr
= 18 km/hr.
Speed upstream = (14 - 4) km/hr
= 10 km/hr..
Let the distance b/w A and B
be x km.
=> x = (x/18+ x/2 / 10)
=> x = 19
=> x = 19x / 180 = 19
=> x= 180.
A man can row upstream at 8 kmph and downstream at 13 kmph. The speed of the stream is
Speed of stream = 1 / 2 (13 - 8 ) kmph
= 1/2 x 5
= 5 /2
A boat covers a certain distance downstream in I hour, while it comes back in 1½ hours. If the speed of the stream be 3 kmph. what is the speed of the boat in still water ?
Let the speed of the boat in still water be x kmph. Then,
Speed downstream = (x + 3) kmph.
Speed upstream = (x - 3) kmph.
= (x - 3)x3/2 kmph.
=> x = 15 kmph
Back To Top